A large body of research shows that occasional catnaps lead to increased productivity in the work place. Managing one's time around naps, as well as optimizing the timing and length of naps, presents challenges and may cause reluctance to take naps. One user may hesitate to doze off while reading a lengthy document for fear of over sleeping. Another user may be in the middle of a time ‘crunch’ and need to stay awake while reading the same document.
In more everyday situations, people generally have regular patterns of drowsiness over the course of a day, such as being sleepy after lunch, or in the later afternoon. Visualizing and incorporating this information into a schedule also presents several challenges. Many users would probably find it useful to have information about their fatigue/drowsiness patterns during the day. They could use it to arrange their schedules, for example.